US4936998A - Filter medium for selectively removing leucocytes - Google Patents

Filter medium for selectively removing leucocytes Download PDF

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US4936998A
US4936998A US07/138,374 US13837487A US4936998A US 4936998 A US4936998 A US 4936998A US 13837487 A US13837487 A US 13837487A US 4936998 A US4936998 A US 4936998A
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filter medium
peripheral surface
surface portion
group
containing
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Takao Nishimura
Yoshiyuki Mizoguchi
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Asahi Medical Co Ltd
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Asahi Medical Co Ltd
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D39/00Filtering material for liquid or gaseous fluids
    • B01D39/14Other self-supporting filtering material ; Other filtering material
    • B01D39/16Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
    • B01D39/1607Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous
    • B01D39/1623Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous of synthetic origin
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61MDEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M1/00Suction or pumping devices for medical purposes; Devices for carrying-off, for treatment of, or for carrying-over, body-liquids; Drainage systems
    • A61M1/36Other treatment of blood in a by-pass of the natural circulatory system, e.g. temperature adaptation, irradiation ; Extra-corporeal blood circuits
    • A61M1/3679Other treatment of blood in a by-pass of the natural circulatory system, e.g. temperature adaptation, irradiation ; Extra-corporeal blood circuits by absorption
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61MDEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2202/00Special media to be introduced, removed or treated
    • A61M2202/04Liquids
    • A61M2202/0413Blood
    • A61M2202/0427Platelets; Thrombocytes
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61MDEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
    • A61M2202/00Special media to be introduced, removed or treated
    • A61M2202/04Liquids
    • A61M2202/0413Blood
    • A61M2202/0439White blood cells; Leucocytes

Abstract

There is disclosed a filter medium for selectively removing leucocytes, which is composed of fibers, each containing nonionic hydrophilic groups and nitrogen-containing basic functional groups at least in its peripheral surface portion. The present filter medium is useful for efficiently removing leucocytes while holding down the loss of platelets to a minimum and, therefore, the present filter medium can be effectively utilized in platelet transfusions and extracorporeal circulation leucocyte removal therapies and the like.

Description

FIELD OF THE INVENTION

The present invention relates to a fibrous filter medium for selectively removing leucocytes. More particularly, the present invention is concerned with a filter medium for selectively removing leucocytes, which is capable of efficiently removing leucocytes, with little loss of platelets, from a cell-containing suspension containing both platelets and leucocytes, represented by blood. Still more particularly, the present invention is concerned with a filter medium which is used as a filter for selectively removing leucocytes, which is capable of removing leucocytes inevitably contained in the blood to be used for, e.g., platelet transfusion while holding down the loss of platelets to the minimum, and which is also capable of removing leucocytes in the extracorporeal circulation leucocyte removal therapy for autoimmune diseases and leukemia while holding down the loss of platelets to a minimum.

DESCRIPTION OF THE PRIOR ART

In the field of blood transfusion, platelet transfusion for improving the bleeding condition of a patient fills an important position. Platelet transfusion includes fresh whole blood transfusion, fresh concentrated red cells transfusion, platelet rich plasma transfusion and platelet concentrate transfusion, and in each type of such transfusions, the blood product usually contains a considerable amount of leucocytes. If a patient repeatedly receives transfusion of blood containing leucocytes, anti-leucocyte antibodies are likely to be produced in the patient. In such a patient, an antigen-antibody reaction occurs between the leucocytes transfused along with the transfused blood and the anti-leucocyte antibodies, causing side effects such as rigor, fever, headache and nausea. It is also known that in blood transfusions, if the transfusion blood contains a large amount of lymphocytes or if the immune system of the blood recipient is weakened for some reason, the so-called GVH reaction is likely to occur. Also, it is recently known that the less the amount of the leucocytes introduced in platelet transfusion, the better the survival of the transfused platelets in the body of the patient. For the above reasons, it has been desired in the field of platelet transfusion to remove leucocytes including lymphocytes as much as possible while holding down the loss of platelets to a minimum.

Meanwhile, the therapies for autoimmune disease and leukemia by extracorporeal circulation have recently been drawing attention as new therapies free from the danger of causing side effects which are often observed in pharmacotherapy. In this case too, of course, it is desired to effectively remove leucocytes including lymphocytes while holding down the loss of platelets to a minimum.

The leucocyte removal from the blood has conventionally been conducted by a centrifugation process using a continuous type centrifuge and the like. However, this process has disadvantages in that the efficiency of leucocyte removal is not so high, that the useful components of the blood including platelets are considerably lost, and that not only expensive apparatus are needed but also cumbersome operations are required.

On the other hand, there has been proposed a filtration process which consists in removing leucocytes by adhering leucocytes onto fibers. This filtration process has advantages in that the leucocyte removal efficiency is high, the loss of erythrocytes and plasma is low, and the operation required is simple and can generally be performed at low cost.

Takenaka et al. disclosed that a filter comprising a mass of fibers having an average diameter of 3 to 10 μm can efficiently entrap leucocytes (see U.S. Pat. No. 4,330,410, British Patent No. 2018151B, French Patent No. 7905629, and West German Patent No. 2908722). Watanabe et al. disclosed that a non-woven fabric filter comprised of fibers having an average diameter of less than 3 μm not only has a high leucocyte' removal efficiency but also can attain an increased rate of treating blood (see Japanese Patent Application Laid-open Specification No. 60-193468 and European Patent Application Publication No. 0155003). However, they do not contain a description with respect to the behavior of platelets, and according to the present inventors' actual experiments in which blood was flowed through these known filters, it was found that a considerable amount of platelet was also removed along with leucocytes.

Kuroda et al. disclosed a method for collecting a leucocyte- and lymphocyte- enriched blood containing less amounts of erythrocytes and platelets by the use of a filter comprising fibers coated with an antithrombotic material (see Japanese Patent Application Laid-open Specification No. 55-129755). However, according to the present inventors' actual experiment in which blood is flowed through this filter, although the loss of platelets was low, the ability to entrap leucocytes was low so that the selective removal of leucocytes could not be attained.

Tsuruta et al. disclosed that a polymer having nitrogen-containing basic functional groups and having a nitrogen content of from 0.05 to 3.5% by weight exhibits an extremely low adhering property for platelets (see Japanese Patent Application Laid-open Specification Nos. 60-119955 to 119957). However, this application does not contain a disclosure about the behavior of leucocytes for the above-mentioned polymer.

As described hereinbefore, there has so far not been known any method that is capable of selectively and efficiently removing leucocytes, with little loss of platelets, from a cell-containing suspension containing both platelets and leucocytes

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a filter medium useful for a filter for selectively removing leucocytes, which is capable of efficiently removing leucocytes while holding down the loss of platelets to a minimum and which is useful in a platelet transfusion and an extracorporeal circulation leucocyte removal therapy.

Not only in the case of a fiber, but also in general, the adhesiveness of cells to a certain material depends on the property of the surface of the material.

It is well known that in order to prevent platelets from adhering to a certain material, a hydrophilic monomer is graft-polymerized onto the surface of the material, or a hydrophilic polymer is coated on the surface of the material. However, the material surfaces obtained by such techniques become less adhesive not only to platelets but also to leucocytes and, therefore, such techniques have never been able to be employed to attain the object of the present invention, that is, provision of a filter medium for selectively removing leucocytes, which is capable of efficiently removing leucocytes by adhesion with little loss of platelets.

In the meantime, it has been a generally observed phenomenon that in a physiological liquid such as one containing cells, the surface of a material having nitrogen-containing basic functional groups turns to have a positive charge and becomes well adhesive to both platelets and leucocytes which have a negative charge.

The present inventors have made extensive and intensive studies with a view to developing a material for selectively adhering leucocytes, which is not adhesive to platelets but adhesive to leucocytes. As result, it has surprisingly been found that a fiber having nonionic hydrophilic groups and nitrogen-containing basic functional groups in its peripheral surface portion and having a basic nitrogen atom content of from 0.2 to 4.0% by weight in the surface portion, has such a property found in no conventional fibers that it is well adhesive to leucocytes while being less adhesive to platelets, and it has also been found that, by using this fiber as material for a filter medium, removal of leucocytes can efficiently be performed while holding down the loss of platelets to a minimum. Based on these novel findings, the present inventors have completed the present invention. That is, according to the present invention, there is provided a filter medium for selectively removing leucocytes, which comprises a plurality of fibers, each comprising a body portion and a peripheral surface portion, and each containing nonionic hydrophilic groups and nitrogen-containing basic functional groups at least in said peripheral surface portion, said peripheral surface portion having a basic nitrogen atom content of from 0.2 to 4.0% by weight.

The reasons for the employment of fibers in the filter medium of the present invention reside in that a fiber form has a large area per unit weight, which is ideal for efficiently removing leucocytes, and that fibers can easily be fabricated into a filter form.

The filter medium of the present invention comprises a plurality of fibers, each of which comprises a body portion and a peripheral surface portion, and at least the peripheral surface portion (hereinafter often referred to as "surface portion") comprises a substance containing nonionic hydrophilic groups and nitrogen-containing basic functional groups. In other words, with respect to each of the fibers to be used in the filter medium of the present invention, the body portion and the peripheral surface portion may be either not integrally or integrally formed, and a portion which is comprised of the above-mentioned portion may be either only the peripheral surface portion, or not only the peripheral surface portion but also the body portion, i.e., the entire fiber. Further, it is not critical whether or not the surfaces of both ends of each fiber, which are included by the body portion of the fiber, are comprised of the above-mentioned substance.

Examples of nonionic hydrophilic groups in the present invention include hydroxyl groups and amido groups. Examples of nitrogen-containing basic functional groups in the present invention include a primary amino group, a secondary amino group, a tertiary amino group, and a quaternary ammonium group, and also include nitrogen-containing aromatic ring groups such as a pyridyl group and an imidazolyl group.

The term "basic nitrogen atom" used herein means a nitrogen atom in the above-mentioned nitrogen-containing basic functional groups, and in the filter medium of the present invention it is requisite that the portion which contains nonionic hydrophilic groups and nitrogen-containing basic functional groups have a basic nitrogen atom content of from 0.2 to 4.0% by weight. If the basic nitrogen atom content is less than 0.2% by weight, the filter medium becomes less adhesive not only to platelets but also to leucocytes, thereby rendering it impossible to selectively remove leucocytes. On the other hand, if the basic nitrogen atom content is more than 4.0% by weight, the filter medium becomes adhesive not only to leucocytes but also to platelets, thus rendering it impossible for leucocytes to be selectively removed. The more preferable range of the basic nitrogen atom content is from 0.3 to 1.5% by weight. With respect to the most suitable contents of the basic nitrogen atoms in various raw materials for the filter medium of the present invention, which are described later, they vary according to the types of the functional groups contained in these raw materials and the conditions under which the filter medium would be used (e.g. they vary heavily depending on the type of an anticoagulant to be added to blood). Various types of anticoagulants may be employed, but there may preferably be used citric acid type anti-coagulants [ACD (acid-citrate-dextrose), CPD (citrate-phosphate-dextrose)] and the like, because they stabilize platelets so that a smooth passage of platelets through a filter is facilitated. When heparin is used as an anticoagulant, filtration of a small amount of blood through a small-sized filter in a short period, of time exhibits no problem, but filtration of a large amount of blood by a largesized filter is likely to activate platelets, so that it becomes difficult for the platelets to pass through the filter.

In the present invention, the molar amount of the nonionic hydrophilic group, in terms of the molar amount of hydroxyl group, amido group, or ethylene oxide unit in polyethylene oxide chains, may preferably be at least equal to, more preferably at least three times as large as the molar amount of the basic nitrogen atom.

The amount of the nitrogen-containing basic functional groups and the amount of the nonionic hydrophilic groups, and the basic nitrogen atom content can be measured by known methods such as an infrared absorptiometric method using a multiple total reflection infrared spectrometer, and elementary analysis.

With respect to the fibers of the filter medium of the present invention, the average fiber diameter is preferably 10 μm or less, more preferably less than 3 μm, since the smaller the averager fiber diameter, the larger the leucocyte removing ability per unit weight of the fiber. However, if the average fiber diameter is less than 0.3 μm, the filter made up of the fibers is not only likely to be clogged, and but also likely to damage the cell wall of erythrocytes, causing hemolysis. Therefore, the average fiber diameter is preferably 0.3 μm or more. In this connection, from the viewpoints of the leucocyte removing ability etc., fibers having an average diameter of from 0.5 to 2.0 μm are most preferred.

The "fiber diameter" used herein is defined by the formula: ##EQU1## wherein x is a diameter of the fiber in μm, W is a weight of the fiber in g, ρ is a density of the fiber in g/cm3, and l is a length of the fiber in cm. The average fiber diameter means the value obtained by averaging the diameters of fibers.

In using the filter medium of the present invention as a leucocyte removing filter, it may be used in the form of a simple mass of fibers or in the form of a woven or non-woven fabric. However, the woven or non-woven fabric form is preferable because with this form, in general, the leucocyte removing performance per unit weight of the filter is high and, in addition, the filter thickness in the direction of the filtration flow can be reduced, so that the pressure loss may be reduced, enabling the blood processing rate to be increased with advantages. Further, in the viewpoint of ease in manufacturing (particularly when the fiber diameter is small), the non-woven fabric form is most preferably employed.

As described before, with respect to each of the fibers used in the filter medium of the present invention, as long as the peripheral surface portion of the fiber is made of a substance containing nonionic hydrophilic groups and nitrogen-containing basic functional groups such as those described before, the fiber structure may be either such that the body portion of the fiber is comprised of a substance which is different in chemical composition from that of the peripheral surface portion, or such that the entire fiber is comprised of a substance containing nonionic hydrophilic groups and nitrogen-containing basic functional groups such as those described before. But, from the viewpoints of ease in manufacturing and cost in production, etc., the former is preferable. FIG. 1 is a diagrammatic cross section of the fiber in the case of the former. Surface portion 1 and body portion 2 have different chemical compositions, and the thickness of surface portion 1, actually, is small as to be almost negligible as compared to the fiber diameter. As mentioned before, in the present invention, it is requisite that surface portion 1 have a specific chemical composition in which nonionic hydrophilic groups and nitrogen-containing basic functional groups are contained, and the content of the basic nitrogen atom is from 0.2 to 4.0% by weight. From the viewpoints of technical ease and total production cost, it is preferred that body portion 2 be first prepared using a later-mentioned general purpose polymer material such as one used for producing a common fiber, and then surface portion 1 having the above-mentioned specific chemical composition be formed thereon. This is more advantageous than the method in which the entire fiber is prepared using the above-mentioned specific chemical composition so that the entire fiber has a uniform structure of the above-mentioned specific chemical composition.

Illustratively stated, in the case where the body portion and peripheral surface portion of the fiber are formed integrally with each other, if the entire fiber is to contain nonionic hydrophilic groups and nitrogen-containing basic functional groups and have a basic nitrogen atom content of from 0.2 to 4.0% by weight, the fiber can be prepared by spinning a polymer produced by the polymerization of later-mentioned monomers. In addition, it is noted that even the fiber having its peripheral surface portion formed integrally with its body portion may have a similar structure to that of FIG. 1 in which surface portion 1 having the above-mentioned specific chemical composition is formed on the peripheral surface of body portion 2. That is, the fiber having such structure may be obtained by a method in which the surface portion of body portion 2 is modified into a substance having the above-mentioned specific chemical composition by, e.g., chemical treatment, ultraviolet ray radiation or low temperature plasma treatment, or a method in which a polymer layer having the above-mentioned specific chemical composition is formed on body portion 2 by surface graft polymerization.

On the other hand, where the peripheral surface portion is formed separately from the body portion, there may be employed a method in which a polymer material containing nonionic hydrophilic groups and nitrogen-containing basic functional groups and having a basic nitrogen atom content of from 0.2 to 4.0% by weight is coated on a fiber material constituting the body portion. This coating method is preferable since it can be generally adopted irrespective of the type of the material of body portion 2. This coating method is also preferable since even if the surface portion of body portion 2 is physically or chemically non-uniform, surface portion 1 having the above-mentioned specific chemical composition can be stably formed thereon. The diagrammatic cross section of the fiber obtained by the above coating method can also be represented by FIG. 1.

As the material for the body portion, there may be employed any of known fibers. Examples of such fibers include synthetic fibers such as polyester fibers, polyamide fibers, polyacrylonitrile fibers, polymethylmethacrylate fibers, polyethylene fibers and polypropylene fibers, semi-synthetic fibers such as cellulose acetate fibers, regenerated fibers such as cuprammonium rayon fibers, viscose rayon fibers, and viscose staple fibers, natural fibers such as cotton fibers, silk and wool, inorganic fibers such as glass fibers and carbon fibers. Of these, synthetic fibers are preferably employed. When a fiber which is produced by spinning is to be employed, a fiber which can easily be spinned, of course, is preferred from the viewpoint of ease in manufacturing.

The surface portion containing hydrophilic groups and nitrogen-containing basic functional groups may preferably have an average thickness of about 10 Å or more. If the thickness is less than 10 Å, it becomes difficult for the body portion to be completely covered by a substance containing nonionic hydrophilic groups and nitrogen-containing basic functional groups, so that it becomes difficult to selectively remove leucocytes while holding down the loss of platelets to a minimum. There is particularly no upper limit for the average thickness. However, when a polymer containing nonionic hydrophilic groups and nitrogen-containing basic functional groups is coated on the body portion or when the peripheral surface portion is formed by graft polymerization, the upper limit for the average thickness of the polymer coating or the graft polymerized peripheral surface portion is preferably less than about 1 μm. If the average thickness is 1 μm or more, the cost for the formation of the peripheral surface portion made of polymer becomes high and, a portion of the surface portion is likely to come off and enter the blood to be processed when the mechanical strength of the formed peripheral surface portion is low. The more preferable range of the average thickness of the peripheral surface portion is from 40 Å to 400 Å.

When peripheral surface portion 1 containing nonionic hydrophilic groups and nitrogen-containing basic functional groups and having a basic nitrogen atom content of from 0.2 to 4.0% by weight is formed on the surface of body portion 2 by surface graft polymerization or polymer coating, there is generally employed a method in which one or more monomers having nonionic hydrophilic groups and one or more monomers having nitrogen-containing basic functional groups are subjected to customary surface graft polymerization, or a method in which a polymer produced by polymerizing the above-mentioned two types of monomers by a usual procedure is coated. With respect to the method for synthesizing a coating material, different types of monomers may be graft copolymerized or block copolymerized, and when the thus obtained coating material is coated on fibers constituting a body portion, there can be formed a microphase separated structure in the peripheral surface portion. Alternatively, there may be employed a method in which a polymer having nonionic hydrophilic groups and a polymer having nitrogen-containing basic functional groups are separately prepared and these two types of polymers are blended just before coating.

Examples of monomers containing nonionic hydrophilic groups which are employable for the above-mentioned graft polymerization or for the synthesis of a polymer for the above-mentioned coating method, includes monomers containing a hydroxyl group or an amido group, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, vinyl alcohol (vinyl acetate is polymerized and then hydrolyzed), (meth)acrylamide and N-vinylpyrrolidone. Examples of nonionic hydrophilic groups also include a polyethylene oxide chain. Of the above-mentioned monomers, 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate are preferably employed from the viewpoints of availability, ease in handling in the polymerization, performance of the resulting surface portion when blood is flowed.

Examples of monomers containing nitrogen-containing basic functional groups include allylamine; (meth)acrylic acid derivatives such as dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, 3-dimethylamino-2-hydroxypropyl (meth)acrylate; styrene derivatives such as p-dimethylaminomethylstyrene, p-diethylaminoethylstyrene; vinyl derivatives of nitrogen-containing aromatic compounds such as 2-vinylpyridine, 4-vinylpyridine, 4-vinylimidazole; and derivatives as obtained by converting the above-mentioned vinyl compounds to a quaternary ammonium salt using a halogenated alkyl or the like. Of these monomers, dimethylaminoethyl (meth)acrylate and diethylaminomethyl (meth)acrylate are preferably employed from the viewpoints of availability, ease in handing in the polymerization, performance of the resulting surface portion when blood is flowed.

In producing the filter medium of the present invention by a method in which the above-mentioned type of polymer material is coated on fibers constituting the body portion, the fiber may be dipped in a solution prepared by dissolving the polymer material in a suitable solvent, and then surplus solution is removed by, e.g., mechanical compression, gravity or centrifugation, followed by drying in dry gas or under vacuum at room temperature or at elevated temperatures.

Before coating, the surface of the fiber may be treated with appropriate chemicals, in order to facilitate the adhesion between the polymer material and the fiber. Further, after the coating, the polymer-coated fiber may be subjected to heat treatment, in order to enhance the adhesion between the fiber and the above-mentioned polymer material or to cause a crosslinking reaction in the coated polymer material for stabilizing the surface portion. In addition, the coating may be conducted simultaneously with, or after the spinning of the fiber. Further, in the case where the filter medium of the present invention is to be used as a filter for removing leucocytes in the form of a woven or non-woven fabric, the coating of the above-mentioned polymer material may be conducted before or after the fabrication of the fibers into the woven or nonwoven fabric form.

When the filter medium of the present invention is employed as a filter for removing leucocytes, the filter medium of the present invention may be packed in a known appropriate filter container for blood filtration which has an inlet and an outlet. The bulk density of the packed filter medium may be varied according to the fiber diameter, but is preferably 0.02 to 0.7 g/cm3. The "bulk density" used herein means a value obtained by dividing the weight of the effective portion of the filter medium packed in a container by the volume of space occupied by the effective portion. When the filter medium of the present invention is used in the form of a woven or non-woven fabric, it may be used as a single sheet of fabric or as a laminate of a plurality of sheets of fabrics depending on the thickness of the sheet. When a laminate of a plurality of sheets is used, the number of sheets is not strictly limited but is usually several to several tens depending on the blood filtration conditions.

PREFERRED EMBODIMENT OF THE INVENTION

The present invention will be described in more detail with reference to the Examples, which should not be construed to be limiting the scope of the present invention.

Examples 1 to 3 and Comparative Examples 1 to 4

A copolymer of 2-hydroxyethyl methacrylate (hereinafter referred to as "HEMA") and diethylaminoethyl methacrylate (hereinafter referred to as "DEAMA") was synthesized by a customary solution radical polymerization. With respect to the polymerization conditions, the polymerization was conducted at 60° C. for 8 hours, using monomers at a monomer concentration of 1 mole/l in ethanol in the presence of 1/200 mole/l of azoisobutylonitrile (AIBN) as an initiator. The thus obtained polymer was subjected to elementary analysis thereby to determine its basic nitrogen atom content. A non-woven fabric (weight : 60 g/m2) of polyethylene terephthalate fibers having an average diameter of 1.8 μm was cut into disks of 25 mm in diameter and these disks were dipped in a 0.1% ethanol solution of the above obtained copolymer, and the surplus of the solution contained in the disks was removed by squeezing. The resultant disks were held in filter holders by two disks per holder and dried by blowing dry air.

The thus obtained coated disks of fabric were set in filter holders (manufactured by Shibata Scientific Technology Ltd., Japan) by two disks per holder to form a filter (thickness, 1.0 mm), and 5 ml of fresh bovine blood, having incorporated therein ACD (acid-citrate-dextrose) as anticoagulant, was flowed through the filter by means of a syringe pump at a constant flow rate of 2 ml/min at room temperature.

Certain amounts of the blood before and after filtration were taken as samples. A blood sample was diluted with Turk's solution and then subjected to a measurement of the leucocyte concentration by using a hemocytometer. At the same time, another blood sample was diluted 100 times with a 1% aqueous ammonium oxalate solution and subjected to a measurement of the platelet concentration by using a hemocytometer (Brecher-Cronkite method). Leucocyte removal ratio and platelet passage ratio were determined by the following equations. ##EQU2##

In Table 1, there are shown the DEAMA unit content (mole %) and the basic nitrogen atom content (% by weight) in the coated copolymer of HEMA and DEAMA, the value of leucocyte removal ratio and the value of platelet passage ratio.

The non-coated filter medium (Comparative Example 4) corresponds to the filter disclosed by Watanabe et al. and the filter medium coated with a polymer containing 0% of DEAMA (i.e. the homo-polymer of HEMA) (Comparative Example 1) corresponds to the filter disclosed by Kuroda et al.

For a filter medium for selectively removing leucocytes with high efficiency and with little loss of platelets, it is practically necessary that the platelet passage ratio be 75% or more and the leucocyte removal ratio be 85% or more.

As apparent from Table 1, in the case of the non-coated filter (the filter of Watanabe et al.) (Comparative Example 4), the leucocyte removal ratio is 88.8%, which is satisfactorily high, but the platelet passage ratio is as low as only 12.9%, that is, selective removal of leucocytes cannot be attained. On the other hand, in the case of the filter coated with the homopolymer of HEMA (the filter of Kuroda et al.) (Comparative Example 1), the platelet passage ratio is satisfactorily 77.0%, but the leucocyte removal ratio is as low as 68.3%, that is, in this case too, selective removal of leucocytes is not attained.

As indicated in Table 1, even in the case where a material containing nonionic hydrophilic groups and nitrogen-containing basic functional groups is used for coating, if the basic nitrogen atom content is low (Comparative Example 2), the platelet passage ratio is as high as 91.6%, but the leucocyte removal ratio is as low as 66.3%, that is, selective removal of leucocytes cannot be attained, whereas if the basic nitrogen atom content is 7.56% which is too high, and the nonionic hydrophilic group content is zero (Comparative Example 3), the leucocyte removal ratio is sufficiently 98.1%, but the platelet passage ratio is as low as 3.2%, that is, in this case too, selective removal of leucocytes is not attained. In contrast, in the case of each of the filter mediums which have basic nitrogen atom contents of 0.53%, 1.03% and 1.98%, respectively, a leucocyte removal ratio of 85% or more is attained while enjoying a platelet passage ratio of 75% or more, that is, selective removal of leucocytes is performed.

                                  TABLE 1__________________________________________________________________________    Comparative           Comparative              Comparative                                           Comparative    Example 1           Example 2                  Example 1                        Example 2                              Example 3                                    Example 3                                           Example__________________________________________________________________________                                           4DEAMA content    0      1      5     10    20    100    Non-coated(mole %)Nitrogen atom    0      0.11   0.53  1.03  1.98  7.56   (0)content (wt %)Leucocyte    68.3   66.3   94.8  96.7  98.6  98.1   88.8removal ratio(%)Platelet 77.0   91.6   88.2  78.8  76.4  3.2    12.9passage ratio(%)__________________________________________________________________________ Leucocyte concentration before filtration 7430 cells/μl Platelet concentration before filtration 147000 cells/μl
EXAMPLES 4 to 6

A copolymer of HEMA and ethyl trimethylmethacrylate ammonium chloride having an ethyl trimethylmethacrylate ammonium chloride monomeric unit content of 5 mole % (the basic nitrogen atom content is 0.52 wt% and the copolymer is hereinafter referred to as "HT"), a copolymer of HEMA, N-vinylpyrrolidone and dimethylaminomethyl methacrylate, in which the contents of the monomeric units are 60 mole %, 30 mole % and 10 mole %, respectively (the basic nitrogen atom content is 1.10 wt% and the copolymer is hereinafter referred to as "HVM"), a copolymer of HEMA, monomethoxy polyethylene glycol methacrylate (the number of the repeating units of ethylene oxide : 23) and DEAMA, in which the contents of the monomeric units are 80 mole %, 5 mole % and 15 mole %, respectively (the basic nitrogen atom content is 1.12 wt% and the copolymer is hereinafter referred to as "HME") were each synthesized by solution polymerization in the same manner as in Example 1. Each of the thus obtained copolymers was coated on a non-woven fabric in the same manner as in Example 1, thereby to obtain filter mediums, and these filter mediums were set in filter holders as described in Example 1, and then bovine blood was flowed through these filter mediums, in order to examine the permeabilities to blood cells.

The results are shown in Table 2. Each of the filter mediums coated with HT, HVM and HME, respectively was found to be a filter medium which is capable of selectively removing leucocytes with a leucocyte removal ratio of 85% or more and a platelet passage ratio of 75% or more.

              TABLE 2______________________________________      Example 4              Example 5   Example 6      H T     H V M       H M E______________________________________Basic nitrogen        0.52      1.10        1.12atom content(wt %)Leucocyte    95.4      93.8        92.3removal ratio(%)Platelet     80.7      83.9        85.1passage ratio(%)______________________________________ Leucocyte concentration before filtration: 5470 cells/μl Platelet concentration before filtration: 273000 cells/μl
EXAMPLE 7

The same non-woven fabric as used in Example 1 was dipped in a 1:1 mixture of N,N-diethylethylenediamine and methanol, thereby to introduce, by ester-amide exchange reaction, amide groups, and hydroxyl groups derived from the ester groups of the polyethylene terephthalate of the non-woven fabric, as nonionic hydrophilic groups, and diethylamino groups as nitrogen-containing basic functional groups onto the surface of the non-woven fabric. The reaction formula is as follows. ##STR1##

The analysis of the surfaces of the fibers by means of a multiple total reflection infrared spectrometer showed that the ratio of the ester linkages to the amido linkages was about 9:1 and the basic nitrogen atom content was about 1.3% by weight.

This non-woven fabric with its surface chemically treated was cut into a disk of 25 mm in diameter to obtain a filter, and blood was flowed therethrough in the same manner as in Example 1 (leucocyte concentration before filtration : 5740 cells/μl, platelet concentration before filtration : 258000 cells/μl).

With respect to the results, the leucocyte removal ratio was 86.5% and the platelet passage ratio was 81.0%, that is, leucocytes were selectively removed.

EXAMPLE 8 AND COMPARATIVE EXAMPLE 5

The same non-woven fabric as used in Example 1 was cut into squares each having a 67 mm×67 mm size, and 20 of them were compiled into a laminate, which was then packed in a column as indicated in FIG. 2. In FIG. 2 non-woven fabric laminate 6 is set in column 3 composed of 2 square frame works 4 and 440 and the peripheral portion of the laminate is firmly pressed together. Numerals 5 and 5' represent projections which are provided inside the column, and which hold the non-woven fabric filter at points in its portion other than the periphery. The non-woven fabric filter has an effective cross-sectional area of 60 mm×60 mm=3600 mm2 and has a thickness of 7 mm. A 0.1% polymer solution in ethanol in which the polymer is a copolymer of HEMA and DEAMA and has a DEAMA unit content of 5 mole% (the basic nitrogen atom content is 0.53 wt%, and the polymer is hereinafter referred to as "HE-5") was flowed through the above-mentioned column having set therein the above-mentioned non-woven fabric, and the fabric set in the column was subsequently dried by blowing dry air and further well dried in vacuum.

2 Liters of fresh bovine blood having incorporated therein anticoagulant ACD was flowed through the thus prepared column at a flow rate of 30 ml/min, at 37° C. in order to examine the leucocyte removal ratio and the platelet passage ratio (the concentrations of leucocytes and platelets before filtration were 5800 cells/μl and 315000 cells/μl, respectively) (Example 8). For comparison, a filter medium not coated with HE-5 was also examined under the same conditions as mentioned above (Comparative Example 5).

The non-coated filter (the filter of Watanabe et al.) exhibited a leucocyte removal ratio of 78.6% and a platelet passage ratio of 78.2% while the filter coated with HE-5 (the filter of the present invention) (Example 8) exhibited a leucocyte removal ratio of 89.3% and a platelet passage ratio of 91.4%. In the case of the non-coated filter, when blood is flowed therethrough in an amount as much as 2 liters, platelets tend to pass therethrough relatively easily, however, the leucocyte removal ratio becomes decreased, so that selective removal of leucocytes cannot be satisfactorily performed. On the other hand, in the case of the filter coated with HE-5, even when such a large amount of blood is flowed, satisfactorily selective removal of leucocytes can be performed. This indicates that the filter medium of the present invention can apply to a leucocyte removal therapy by the extracorporeal circulation method.

EXAMPLE 9

A non-woven fabric made of polyethylene terephthalate fibers having an average diameter of 4.7 μm (weight : 88 g/m2) was cut into squares each having a 67 mm×67 mm size and 14 of them were packed in columns in the same manner as in Example 8, followed by subjecting to coating treatment with HE-5. When 400 ml of fresh bovine blood (leucocyte concentration : 4830 cells/μl, platelet concentration : 284000 cells/μl) was flowed through the thus obtained filter in the same manner as in Example 8, there were obtained a leucocyte removal ratio of 86.1% and a platelet passage ratio of 92.3%, that is, selective removal of leucocytes was performed.

Example 10 and Comparative Example 6

The same non-woven fabric as used in Example 1 was cut into squares each having a 67 mm×67 mm size and 12 of them were compiled into a laminate, which was then packed in a column and subjecting to coating with HE-5 polymer in the same manner as in Example 8. 500 ml of platelet rich plasma (leucocyte concentration : 413 cells/μl, platelet concentration : 299000 cells/μl) prepared by centrifuging fresh bovine blood having incorporated therein ACD was flowed through the above obtained column by the force of gravity at a head of 80 cm (Example 10). For comparison, a non-coated filter medium was also examined under the same conditions as mentioned above (Comparative Example 6).

The non-coated filter exhibited a leucocyte removal ratio as high as 100% but a platelet passage ratio as low as 69.7%, whereas the filter coated with HE-5 exhibited a leucocyte removal ratio of 100% and a platelet passage ratio of 93.8%, that is, leucocytes were selectively removed with little loss of platelets.

Example 11 and Comparative Example 7

The same non-woven fabric as used in Example 1 was cut into disks each having a diameter of 70 mm and 8 of them were compiled into a laminate, which was then packed in a column so that the column filter has an effective cross-sectional area of 28.3 cm2 and a thickness of 4 mm, and subsequently subjected to coating with HE-5 polymer in the same manner as in Example 8. 300 ml of platelet concentrate (leucocyte concentration : 4675 cells/μl, platelet concentration : 550000 cells/μl) prepared by centrifuging fresh bovine blood having incorporated therein ACD was flowed through the above obtained column by the force of gravity at a head of 80 cm (Example 11). For comparison, a non-coated filter medium was also examined under the same conditions as mentioned above (Comparative Example 7).

The non-coated filter exhibited a leucocyte removal ratio as high as 93.1%, but a platelet passage ratio as low as 60.5%, whereas the filter coated with HE-5 exhibited a leucocyte removal ratio of 92.0% and a platelet passage ratio of 88.1%, which are both high, that is, leucocytes were selectively removed with little loss of platelets.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagrammatic cross-sectional view of a fiber used for the filter medium of the present invention, which comprises a peripheral surface portion and a body portion having a different chemical composition from that of the peripheral surface portion. 1 : peripheral surface portion of the fiber 2 : body portion of the fiber

FIG. 2 is a cross-sectional side view of one form of a filter (column) having packed therein a filter medium of the present invention. 3 : column body 4, 4' : square-shaped frames 5, 5' : projections 6 : non-woven fabric filter layer 7 : blood inlet 8: blood outlet

Probability of Utilization in Industry

The filter medium of the present invention is extremely useful for selectively removing leucocytes with high efficiency and with little loss of platelets. It is expected that by the removal of leucocytes contained in a blood product for platelet transfusions by using the filter medium of the present invention, the side effects due to the transfusions will be reduced and, further, the life of transfused platelets would be prolonged. It is further expected that when the filter medium of the present invention is employed in an extracorporeal circulation leucocyte removal therapy for patients of autoimmune diseases and leukemia, leucocytes would be removed efficiently in a shortened period of time and almost no other useful blood components would be lost and, hence, the burden on the patient would be little, providing an excellent remedial effect.

Claims (26)

What is claimed is:
1. A method for selectively removing leukocytes from a suspension containing leucocytes and platelets, comprising:
contacting a suspension containing leucocytes and platelets with a filter medium,
said filter medium comprising a plurality of fibers, each comprising a body portion and a peripheral surface portion, at least said peripheral surface portion of which comprises a polymer obtained by polymerization of at least one vinyl monomer having a nonionic hydrophilic group with at least one vinyl monomer having a nitrogen-containing basic functional group and has a basic nitrogen atom content of from 0.2 to 4.0% by weight,
thereby causing said leucocytes to selectively adhere to said filter medium while allowing the resultant platelet-enriched suspension substantially free of leucocytes to pass through said filter medium, and
collecting said platelet-enriched suspension, and wherein said collected platelet-enriched suspension is adapted to be used for platelet transfusion or to be returned to a donor of said suspension containing leucocytes and platelets for performing extracorporeal leucocyte removal therapy.
2. The method according to claim 1; wherein the basic nitrogen atom content of said peripheral surface portion is from 0.2 to 1.5% by weight.
3. The method according to claim 1, wherein the average fiber diameter is from 10 μm or less.
4. The method according to claim 3, wherein the average fiber diameter is from 0.3 μm to less than 3.0 μm.
5. The method according to claim 1, wherein said filter medium is in the form of a non-woven fabric.
6. The method according to claim 1, wherein said peripheral surface portion is formed integrally with or separately from said body portion and said body portion has a chemical composition different from that of said peripheral surface portion.
7. The method according to claim 6, wherein said peripheral surface portion comprises a polymer containing nonionic hydrophilic groups and nitrogen-containing basic functional groups, and has a basic nitrogen atom content of from 0.2 to 4.0% by weight, said peripheral surface portion being comprised of a coating formed on said body portion having a chemical composition different from that of said polymer.
8. The method according to claim 6, wherein said peripheral surface portion is formed integrally with said body portion.
9. The method according to any one of claims 1 to 3, wherein the basic nitrogen atom content of said peripheral surface portion is from 0.3 to 1.5% by weight.
10. The method according to claim 1, wherein said peripheral surface portion is formed integrally with said body portion, and each of said body portion and said peripheral surface portion contains nonionic hydrophilic groups and nitrogen-containing basic functional groups and has a basic nitrogen atom content of from 0.2 to 4.0% by weight.
11. The method according to claim 1, wherein said nonionic hydrophilic group is a hydroxyl group, an amide group, a polyethylene oxide chain or mixtures thereof, and said nitrogen-containing basic functional group is a primary amino group, a secondary amino group, a tertiary amino group, a quaternary ammonium group, a nitrogen-containing aromatic ring group or mixtures thereof.
12. The method according to claim 1, wherein said vinyl monomer having a nonionic hydrophilic group is selected from the group consisting of 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, vinyl alcohol, (meth)acrylamide, N-vinyl pyrrolidone and monomethoxy polyethylene glycol methacrylate.
13. The method according to claim 1, wherein said vinyl monomer having a nitrogen-containing basic functional group is selected from vinyl compounds of the group consisting of allylamine, (meth)acrylic acid derivatives, styrene derivatives and vinyl derivatives of nitrogen-containing aromatic compounds, and from derivatives obtained by converting said vinyl compounds to quaternary ammonium salts.
14. A filter medium for selectively removing leucocytes, which comprises a plurality of fibers, each comprising
a body portion and a peripheral surface portion, at least said peripheral surface portion of which comprises a polymer obtained by polymerization of at least one vinyl monomer having a nonionic hydrophilic group with at least one vinyl monomer having a nitrogen-containing basic functional group and has a basic nitrogen atom content of from 0.2 to 4.0% by weight,
said filter medium being for use in collecting a substantially leucocyte free, platelet-enriched suspension from a suspension containing leucocytes and platelets, said collected platelet-enriched suspension being adapted to be used for platelet transfusion or to be returned to a donor of said suspension containing leucocytes and platelets for performing extracorporeal leucocyte removal therapy.
15. A filter medium according to claim 14, wherein each fiber has a diameter of from 10 μm or less.
16. The filter medium according to claim 14, wherein each fiber has a diameter of from 0.3 μm to less than 3.0 μm.
17. The filter medium according to any one of claims 14 to 16, which is in the form of a non-woven fabric.
18. The filter medium according to any one of claims 14 to 16, wherein said peripheral surface portion is formed integrally with or separately from said body portion and said body portion has a chemical composition different from that of said peripheral surface portion.
19. The filter medium according to claim 18, wherein said peripheral surface portion comprises a polymer containing nonionic hydrophilic groups and nitrogen-containing basic functional groups, and has a basic nitrogen atom content of from 0.2 to 4.0% by weight, said peripheral surface portion being comprised of a coating formed on said body portion having a chemical composition different from that of said polymer.
20. The filter medium according to claim 18, wherein said peripheral surface portion is formed integrally with said body portion.
21. The filter medium according to any one of claims 14 to 16, wherein the basic nitrogen atom content of said peripheral surface portion which contains nonionic hydrophilic groups and nitrogen-containing basic functional groups is from 0.3 to 1.5% by weight.
22. The filter medium according to claim 14, wherein said peripheral surface portion is formed integrally with said body portion, and each of said body portion and said peripheral surface portion contains nonionic hydrophilic groups and nitrogen-containing basic functional groups and has a basic nitrogen atom content of from 0.2 to 4.0% by weight.
23. The filter medium according to claim 14, wherein said nonionic hydrophilic group is a hydroxyl group, an amide group, a polyethylene oxide chain or mixtures thereof, and said nitrogen-containing basic functional group is a primary amino group, a secondary amino group, a tertiary amino group, a quaternary ammonium group, a nitrogen-containing aromatic ring group or mixtures thereof.
24. The filter medium according to claim 14, wherein said vinyl monomer having a nonionic hydrophilic group is selected from the group consisting of 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, vinyl alcohol, (meth)acrylamide, N-vinyl pyrrolidone and monomethoxy polyethylene glycol methacrylate.
25. The filter medium according to claim 14, wherein said vinyl monomer having a nitrogen-containing basic functional group is selected from vinyl compounds of the group consisting of allylamine, (meth)acrylic acid derivatives, styrene derivatives and vinyl derivatives of nitrogen-containing aromatic compounds, and from derivatives obtained by converting said vinyl compounds to quaternary ammonium salts.
26. The filter medium according to claim 14, wherein the basic nitrogen atom content of said peripheral surface portion is from 0.2 to 1.5% by weight.
US07/138,374 1986-03-28 1987-03-28 Filter medium for selectively removing leucocytes Expired - Lifetime US4936998A (en)

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Cited By (105)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5133878A (en) * 1989-11-17 1992-07-28 Pall Corporation Polymeric microfiber filter medium
US5151192A (en) * 1990-07-13 1992-09-29 Pall Corporation Method for removing heparin from blood or plasma
WO1993001880A1 (en) * 1991-07-22 1993-02-04 Lydall, Inc. Blood filter and method of filtration
US5258127A (en) * 1990-07-27 1993-11-02 Pall Corporation Leucocyte depleting filter device and method of use
US5258126A (en) * 1989-09-12 1993-11-02 Pall Corporation Method for obtaining platelets
US5266219A (en) * 1989-12-28 1993-11-30 Pall Corporation Device and method for separating plasma from blood
US5298165A (en) * 1990-09-25 1994-03-29 Asahi Medical Co., Ltd. Method for removing leukocytes and a filter system for removing the same
US5302299A (en) * 1990-05-24 1994-04-12 Pall Corporation Biological semi-fluid processing assembly
AU649415B2 (en) * 1989-09-12 1994-05-26 Pall Corporation Processing blood
US5344561A (en) * 1989-05-09 1994-09-06 Pall Corporation Device for depletion of the leucocyte content of blood and blood components
US5360545A (en) * 1989-09-12 1994-11-01 Pall Corporation Filter for obtaining platelets
US5362406A (en) * 1990-07-27 1994-11-08 Pall Corporation Leucocyte depleting filter device and method of use
WO1995003113A1 (en) * 1993-07-26 1995-02-02 Pall Corporation Cardioplegia filter
US5399268A (en) * 1989-09-12 1995-03-21 Pall Corporation Method for processing blood for human transfusion
US5407581A (en) * 1992-03-17 1995-04-18 Asahi Medical Co., Ltd. Filter medium having a limited surface negative charge for treating a blood material
US5443743A (en) * 1991-09-11 1995-08-22 Pall Corporation Gas plasma treated porous medium and method of separation using same
US5445736A (en) * 1989-09-12 1995-08-29 Pall Corporation Device and filter element for processing blood for human transfusion
US5472605A (en) * 1994-03-10 1995-12-05 Hemasure, Inc. Filtration device useable for removal of leukocytes and other blood components
US5476587A (en) * 1993-06-27 1995-12-19 Terumo Kabushiki Kaisha Leukocyte-separating filter and leukocytes remover
US5478470A (en) * 1991-08-22 1995-12-26 Asahi Medical Co., Ltd. Filter material for selectively removing leukocytes
US5498336A (en) * 1991-02-22 1996-03-12 Terumo Kabushiki Kaisha Leukocyte-removing filter and leukocyte-removing apparatus furnished therewith
US5543062A (en) * 1992-10-07 1996-08-06 Asahi Medical Co., Ltd. Leukocyte-removing filter device and system and method of using thereof
US5582907A (en) * 1994-07-28 1996-12-10 Pall Corporation Melt-blown fibrous web
WO1996040405A1 (en) 1995-06-07 1996-12-19 Baxter International Inc. System for deriving collected blood storage parameters
WO1996040400A1 (en) 1995-06-07 1996-12-19 Baxter International Inc. Blood processing systems which monitor citrate return
US5591337A (en) * 1993-09-14 1997-01-07 Baxter International Inc. Apparatus for filtering leukocytes from blood cells
US5630946A (en) * 1995-02-15 1997-05-20 Pall Corporation Method for processing a biological fluid including leukocyte removal in an extracorporeal circuit
US5639376A (en) * 1994-01-10 1997-06-17 Hemasure, Inc. Process for simultaneously removing leukocytes and methylene blue from plasma
US5647985A (en) * 1994-10-17 1997-07-15 Baxter International Inc. Whole blood leukodepletion and platelet filter
US5648070A (en) * 1991-12-04 1997-07-15 Cobe Laboratories, Inc. Biocompatible anion exchange materials
US5674173A (en) * 1995-04-18 1997-10-07 Cobe Laboratories, Inc. Apparatus for separating particles
US5695653A (en) * 1994-12-23 1997-12-09 Pall Corporation Device and method for separating components from a biological fluid
US5707526A (en) * 1993-02-09 1998-01-13 Menachem Kraus Leukocyte removal method using a nitrocellulose membrane filter unit
EP0570569B1 (en) * 1991-12-04 1998-02-25 Hospal Industrie A support material and biocompatible anion exchange materials
US5728306A (en) * 1994-12-23 1998-03-17 Baxter International Inc. Leukodepletion filter and method for filtering leukocytes from freshly drawn blood
US5783094A (en) * 1995-04-13 1998-07-21 Teva Medical Ltd. Whole blood and platelet leukocyte filtration method
US5817237A (en) * 1994-01-10 1998-10-06 Hemasure, Inc. Process for simultaneously removing leukocytes and methylene blue from plasma
US5863436A (en) * 1990-05-24 1999-01-26 Pall Corporation Venting system
US5906570A (en) * 1995-04-18 1999-05-25 Cobe Laboratories, Inc. Particle filter apparatus
US5939319A (en) * 1995-04-18 1999-08-17 Cobe Laboratories, Inc. Particle separation method and apparatus
US5972217A (en) * 1994-10-17 1999-10-26 Baxter International Inc. Blood cell separation devices having a membrane with particular coating
US6010633A (en) * 1997-03-06 2000-01-04 Hemasure Inc. Method of preventing air from becoming entrapped within a filtration device
US6022306A (en) * 1995-04-18 2000-02-08 Cobe Laboratories, Inc. Method and apparatus for collecting hyperconcentrated platelets
US6045701A (en) * 1994-10-17 2000-04-04 Baxter International Inc. Method of filtering a fluid suspension with a membrane having a particular coating
US6048464A (en) * 1995-12-26 2000-04-11 Asahi Medical Co., Ltd. Filter medium for leukocyte removal, method of making, and method of using thereof
US6051146A (en) * 1998-01-20 2000-04-18 Cobe Laboratories, Inc. Methods for separation of particles
US6053856A (en) * 1995-04-18 2000-04-25 Cobe Laboratories Tubing set apparatus and method for separation of fluid components
US6074869A (en) * 1994-07-28 2000-06-13 Pall Corporation Fibrous web for processing a fluid
US6086770A (en) * 1990-05-24 2000-07-11 Pall Corporation Venting system
EP1018346A2 (en) * 1999-01-07 2000-07-12 Terumo Kabushiki Kaisha Leucocyte filter and method for manufacturing same
WO2000053287A1 (en) * 1999-03-11 2000-09-14 Whatman, Inc. Leukocyte filter assembly, media, and method
US6153113A (en) * 1999-02-22 2000-11-28 Cobe Laboratories, Inc. Method for using ligands in particle separation
AU726974B2 (en) * 1997-08-28 2000-11-30 Asahi Kasei Medical Co., Ltd. Leucocyte-removing filter medium
US6251292B1 (en) 1994-03-10 2001-06-26 Hemasure, Inc. Method of preventing air from becoming entrapped within a filtration device
US6274041B1 (en) 1998-12-18 2001-08-14 Kimberly-Clark Worldwide, Inc. Integrated filter combining physical adsorption and electrokinetic adsorption
US6306454B1 (en) 1994-10-17 2001-10-23 Baxter International Inc. Method for producing improved medical devices and devices so produced
US6334842B1 (en) 1999-03-16 2002-01-01 Gambro, Inc. Centrifugal separation apparatus and method for separating fluid components
US20020000403A1 (en) * 2000-05-17 2002-01-03 Masaru Tanaka Copolymers and blood filter using the same
US6337026B1 (en) 1999-03-08 2002-01-08 Whatman Hemasure, Inc. Leukocyte reduction filtration media
US6354986B1 (en) 2000-02-16 2002-03-12 Gambro, Inc. Reverse-flow chamber purging during centrifugal separation
EP1192959A2 (en) * 2000-09-29 2002-04-03 Terumo Kabushiki Kaisha Antithrombotic surface treating agent and medical apparatus
WO2002060557A1 (en) * 2001-01-29 2002-08-08 Asahi Medical Co., Ltd. Filter for processing blood and process for producing the same
US6537614B1 (en) 1998-12-18 2003-03-25 Kimberly-Clark Worldwide, Inc. Cationically charged coating on hydrophobic polymer fibers with poly (vinyl alcohol) assist
US20030104349A1 (en) * 2001-12-05 2003-06-05 Baxter International Inc. Manual processing systems and methods for providing blood components conditioned for pathogen inactivation
US20030106861A1 (en) * 2001-12-10 2003-06-12 Gibbs Bruce M. Methods and apparatus for leukoreduction of red blood cells
US20030173274A1 (en) * 2002-02-01 2003-09-18 Frank Corbin Blood component separation device, system, and method including filtration
US20030189003A1 (en) * 2002-04-08 2003-10-09 Menahem Kraus Leukocyte filter construction
US6632191B1 (en) * 1994-10-13 2003-10-14 Haemonetics Corporation System and method for separating blood components
US6645388B2 (en) 1999-12-22 2003-11-11 Kimberly-Clark Corporation Leukocyte depletion filter media, filter produced therefrom, method of making same and method of using same
US6709868B2 (en) 2002-05-20 2004-03-23 Portascience Inc. Method and apparatus for measuring white blood cell count
US6746482B2 (en) 1994-10-17 2004-06-08 Baxter International Inc. Method for producing medical devices and devices so produced
EP1452193A1 (en) * 2001-12-03 2004-09-01 ASAHI MEDICAL Co., Ltd. Filter for selectively eliminating leukocytes
US20040253204A1 (en) * 2001-07-31 2004-12-16 Yasuhiko Yagi Polymer for coating leukocyte removal filter material and the filter material
US20050014127A1 (en) * 2001-10-16 2005-01-20 Hirokazu Onodera Method for selectively removing virus and leukocytes eliminating material and eliminating apparatus
US20050137517A1 (en) * 2003-12-19 2005-06-23 Baxter International Inc. Processing systems and methods for providing leukocyte-reduced blood components conditioned for pathogen inactivation
US6977044B1 (en) 1999-11-01 2005-12-20 Asahi Medical Co., Ltd. Filter for selectively removing leukocytes
WO2006016166A1 (en) * 2004-08-13 2006-02-16 Asahi Kasei Kabushiki Kaisha Polymers useful as medical materials
WO2006016163A1 (en) * 2004-08-13 2006-02-16 Asahi Kasei Kabushiki Kaisha Polymers useful as medical materials
US20070029256A1 (en) * 2003-08-07 2007-02-08 Yasuhiro Nakano Composite porous membrane and process for producing the same
US20070118063A1 (en) * 2005-10-05 2007-05-24 Gambro, Inc Method and Apparatus for Leukoreduction of Red Blood Cells
US7279107B2 (en) 2002-04-16 2007-10-09 Gambro, Inc. Blood component processing system, apparatus, and method
WO2007134191A1 (en) * 2006-05-10 2007-11-22 Board Of Regents, The University Of Texas System Detecting multiple types of leukocytes
US20080038738A1 (en) * 2006-05-10 2008-02-14 The Board Of Regents Of The University Of Texas System Detecting tumor biomarker in oral cancer
US20090014395A1 (en) * 1996-02-23 2009-01-15 Bischof Daniel F Systems and Methods for On Line Finishing of Cellular Blood Products Like Platelets Harvested for Therapeutic Purposes
US7651474B2 (en) 1999-10-01 2010-01-26 Caridianbct, Inc. Method and apparatus for leukoreduction of red blood cells
US20100051533A1 (en) * 2000-07-10 2010-03-04 Asahi Medical Co., Ltd Blood processing filter
WO2010113632A1 (en) 2009-03-30 2010-10-07 テルモ株式会社 Surface-treating agent, filtering material for filter, and blood treatment filter
US20100270232A1 (en) * 2007-12-27 2010-10-28 Toray Industries, Inc. Fiber construct for treating biological components
US20100291588A1 (en) * 2005-06-24 2010-11-18 The Board Of Regents Of The University Of Texas System Systems and methods including self-contained cartridges with detection systems and fluid delivery systems
CN101053683B (en) 2006-02-20 2010-12-15 旭化成医疗株式会社 Method for filtering blood or blood components and filter device
US8101431B2 (en) 2004-02-27 2012-01-24 Board Of Regents, The University Of Texas System Integration of fluids and reagents into self-contained cartridges containing sensor elements and reagent delivery systems
CN102397724A (en) * 2010-09-16 2012-04-04 私立中原大学 Filter medium for leukocyte removal and filter method
US8377398B2 (en) 2005-05-31 2013-02-19 The Board Of Regents Of The University Of Texas System Methods and compositions related to determination and use of white blood cell counts
EP2783717A1 (en) 2013-03-27 2014-10-01 Maco Pharma Leucocyte filtration unit with reduced platelets adherence
CN104117230A (en) * 2013-04-24 2014-10-29 富士胶片株式会社 Filter, filtering method, acylate cellulose film and making method thereof
US9248446B2 (en) 2013-02-18 2016-02-02 Terumo Bct, Inc. System for blood separation with a separation chamber having an internal gravity valve
US20160106779A1 (en) * 2004-08-20 2016-04-21 Allan Mishra Neutrophil-depleted whole blood and platelet rich plasma compositions
CN106319966A (en) * 2016-08-18 2017-01-11 南京双威生物医学科技有限公司 Processing method of leucocyte filter membrane
CN106457205A (en) * 2014-07-22 2017-02-22 旭化成医疗株式会社 Adsorbent for removing histone and purification device for liquid derived from living organism
US9782707B2 (en) 2014-03-24 2017-10-10 Fenwal, Inc. Biological fluid filters having flexible walls and methods for making such filters
US9796166B2 (en) 2014-03-24 2017-10-24 Fenwal, Inc. Flexible biological fluid filters
US9968738B2 (en) 2014-03-24 2018-05-15 Fenwal, Inc. Biological fluid filters with molded frame and methods for making such filters
US10159778B2 (en) 2014-03-24 2018-12-25 Fenwal, Inc. Biological fluid filters having flexible walls and methods for making such filters
US10214727B2 (en) 2013-06-04 2019-02-26 Allan Mishra Platelet-rich plasma compositions and methods of preparation
US10376627B2 (en) 2014-03-24 2019-08-13 Fenwal, Inc. Flexible biological fluid filters

Families Citing this family (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2243794B (en) * 1987-10-20 1992-07-01 Pall Corp Separating devices
US4923620A (en) * 1987-10-20 1990-05-08 Pall Corporation Device for depletion of the leukocyte content of blood and blood components
US4925572A (en) * 1987-10-20 1990-05-15 Pall Corporation Device and method for depletion of the leukocyte content of blood and blood components
IL88081D0 (en) * 1987-10-20 1989-06-30 Pall Corp Device and method for depletion of the leucocyte content of blood and blood components
US4880548A (en) * 1988-02-17 1989-11-14 Pall Corporation Device and method for separating leucocytes from platelet concentrate
DE68902698T2 (en) * 1988-06-23 1993-04-22 Asahi Medical Co A method for separating blood into blood components and unit for separation of blood components.
EP0397403B1 (en) * 1989-05-09 1993-12-22 Pall Corporation Device and method for depletion of the leucocyte content of blood and blood components
US5229012A (en) * 1989-05-09 1993-07-20 Pall Corporation Method for depletion of the leucocyte content of blood and blood components
US5089146A (en) * 1990-02-12 1992-02-18 Miles Inc. Pre-storage filtration of platelets
DE69228695T2 (en) * 1991-09-11 1999-10-14 Pall Corp Gas plasma treated porous medium and method of separation using the medium
GB2277886A (en) * 1990-07-27 1994-11-16 Pall Corp Leucocyte depleting filter
DE69119683D1 (en) * 1990-07-27 1996-06-27 Pall Corp Filter means for removing leukocytes and method of use
US5217627A (en) * 1990-11-06 1993-06-08 Pall Corporation System and method for processing biological fluid
US5100564A (en) * 1990-11-06 1992-03-31 Pall Corporation Blood collection and processing system
US5547576A (en) * 1992-07-06 1996-08-20 Terumo Kabushiki Kaisha Pathogenic substance removing material and a blood filter containing the material
US5523004A (en) * 1992-12-04 1996-06-04 Terumo Kabushiki Kaisha Method for treatment of blood using a blood bag
DE69314154D1 (en) * 1992-12-28 1997-10-30 Asahi Medical Co Filter material, apparatus and methods for separating leukocytes
CA2178523C (en) 1995-06-09 2001-08-28 Tomohiro Kitagawa Plasma separation filter, plasma separation method using the same and plasma separation apparatus
CA2367694C (en) * 1999-03-16 2008-08-05 Pall Corporation Biological fluid filter and system
US6945411B1 (en) 1999-03-16 2005-09-20 Pall Corporation Biological fluid filter and system
EP1262204A4 (en) * 2000-03-10 2007-06-20 Asahi Medical Co Novel leukapheretic filter
JP2002161048A (en) * 2000-11-24 2002-06-04 Terumo Corp Filter for preparing platelet release factor and method for preparing platelet release factor
JP4565762B2 (en) * 2001-03-26 2010-10-20 旭化成メディカル株式会社 Leukocyte removal filter and method for producing the same
TW200505394A (en) 2003-06-06 2005-02-16 Asahi Medical Co Material promoting wound healing
ES2280656T3 (en) * 2003-07-03 2007-09-16 Fresenius Hemocare Italia S.R.L. Filter for the elimination of substances of blood products.
JP2006142241A (en) * 2004-11-22 2006-06-08 Nippon Adabaio Kk Carrier for adsorbing blood ingredient
JPWO2017141752A1 (en) * 2016-02-15 2018-11-08 旭化成メディカル株式会社 Blood treatment filter

Citations (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS55129755A (en) * 1979-03-30 1980-10-07 Asahi Chem Ind Co Ltd Catch and pick-up filter of white corpuscle
GB2062498A (en) * 1979-10-09 1981-05-28 Asahi Chemical Ind Separation of leukocytes or lymphocytes from leukocyte-containing suspension
US4330410A (en) * 1978-03-06 1982-05-18 Asahi Kasei Kogyo Kabushiki Kaisha Separation of leukocytes from leukocyte-containing suspension by filtration
JPS59203565A (en) * 1983-05-02 1984-11-17 Asahi Chemical Ind Improved blood purifying membrane and production thereof
JPS60119955A (en) * 1983-12-02 1985-06-27 Teiji Tsuruta Synthetic polymer body for living body material
JPS60119956A (en) * 1983-12-02 1985-06-27 Teiji Tsuruta Synthetic polymer for living body material
JPS60119957A (en) * 1983-12-02 1985-06-27 Teiji Tsuruta Synthetic polymer for living body material
JPS6148376A (en) * 1984-08-13 1986-03-10 Asahi Chemical Ind Improved blood purification membrane and its production
JPS6148375A (en) * 1984-08-13 1986-03-10 Asahi Chemical Ind Improved blood purification membrane and its production
JPS6148373A (en) * 1984-08-13 1986-03-10 Asahi Chemical Ind Improved blood purification membrane and its production
JPS61226056A (en) * 1985-03-29 1986-10-07 Nippon Medical Supply Blood filter
US4617124A (en) * 1982-07-13 1986-10-14 Pall Corporation Polymeric microfibrous filter sheet, preparation and use
US4620932A (en) * 1983-06-06 1986-11-04 Howery Kenneth A Submicronic hydrophilic filter media
JPS61253071A (en) * 1985-05-07 1986-11-10 Asahi Medical Co Blood purifying apparatus
US4701267A (en) * 1984-03-15 1987-10-20 Asahi Medical Co., Ltd. Method for removing leukocytes

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2807383B2 (en) * 1992-11-02 1998-10-08 株式会社東芝 Operational limits monitoring device

Patent Citations (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4330410A (en) * 1978-03-06 1982-05-18 Asahi Kasei Kogyo Kabushiki Kaisha Separation of leukocytes from leukocyte-containing suspension by filtration
JPS55129755A (en) * 1979-03-30 1980-10-07 Asahi Chem Ind Co Ltd Catch and pick-up filter of white corpuscle
GB2062498A (en) * 1979-10-09 1981-05-28 Asahi Chemical Ind Separation of leukocytes or lymphocytes from leukocyte-containing suspension
US4416777A (en) * 1979-10-09 1983-11-22 Asahi Kasei Kogyo Kabushiki Kaisha Separation of leukocytes or lymphocytes from leukocyte-containing suspension
US4617124A (en) * 1982-07-13 1986-10-14 Pall Corporation Polymeric microfibrous filter sheet, preparation and use
JPS59203565A (en) * 1983-05-02 1984-11-17 Asahi Chemical Ind Improved blood purifying membrane and production thereof
US4620932A (en) * 1983-06-06 1986-11-04 Howery Kenneth A Submicronic hydrophilic filter media
JPS60119955A (en) * 1983-12-02 1985-06-27 Teiji Tsuruta Synthetic polymer body for living body material
JPS60119956A (en) * 1983-12-02 1985-06-27 Teiji Tsuruta Synthetic polymer for living body material
JPS60119957A (en) * 1983-12-02 1985-06-27 Teiji Tsuruta Synthetic polymer for living body material
US4701267A (en) * 1984-03-15 1987-10-20 Asahi Medical Co., Ltd. Method for removing leukocytes
US4701267B1 (en) * 1984-03-15 1996-03-12 Asahi Medical Co Method for removing leukocytes
JPS6148373A (en) * 1984-08-13 1986-03-10 Asahi Chemical Ind Improved blood purification membrane and its production
JPS6148375A (en) * 1984-08-13 1986-03-10 Asahi Chemical Ind Improved blood purification membrane and its production
JPS6148376A (en) * 1984-08-13 1986-03-10 Asahi Chemical Ind Improved blood purification membrane and its production
JPS61226056A (en) * 1985-03-29 1986-10-07 Nippon Medical Supply Blood filter
JPS61253071A (en) * 1985-05-07 1986-11-10 Asahi Medical Co Blood purifying apparatus

Non-Patent Citations (6)

* Cited by examiner, † Cited by third party
Title
Biomaterials, vol. 6, Nov. 1985, pp. 409 415, Butterworth & Co., GB, N. Yui et al., Reversibility of Granulocyte Adhesion Using Polyamine grafted Nylon 6 as a New Column Substrate for Granulocyte Separation . *
Biomaterials, vol. 6, Nov. 1985, pp. 409-415, Butterworth & Co., GB, N. Yui et al., "Reversibility of Granulocyte Adhesion Using Polyamine-grafted Nylon-6 as a New Column Substrate for Granulocyte Separation".
Chemical Abstracts, vol. 97, No. 2, Jul. 12, 1982, p. 365, K. Sanui et al, "Effect of Microphase Separated Structure in Platelets Adhesion on Graft Polyamides".
Chemical Abstracts, vol. 97, No. 2, Jul. 12, 1982, p. 365, K. Sanui et al, Effect of Microphase Separated Structure in Platelets Adhesion on Graft Polyamides . *
Derwent Abstract 85 193,172, Synthetic High Polymer for Artificial Organs Production . *
Derwent Abstract 85-193,172, "Synthetic High Polymer for Artificial Organs Production".

Cited By (173)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5501795A (en) * 1989-05-09 1996-03-26 Pall Corporation Device for depletion of the leucocyte content of blood and blood components
US5344561A (en) * 1989-05-09 1994-09-06 Pall Corporation Device for depletion of the leucocyte content of blood and blood components
US5445736A (en) * 1989-09-12 1995-08-29 Pall Corporation Device and filter element for processing blood for human transfusion
US5543060A (en) * 1989-09-12 1996-08-06 Pall Corporation Method for processing blood for human transfusion
US5580465A (en) * 1989-09-12 1996-12-03 Pall Corporation Method for preparing platelets
US5360545A (en) * 1989-09-12 1994-11-01 Pall Corporation Filter for obtaining platelets
US5258126A (en) * 1989-09-12 1993-11-02 Pall Corporation Method for obtaining platelets
US5399268A (en) * 1989-09-12 1995-03-21 Pall Corporation Method for processing blood for human transfusion
AU649415B2 (en) * 1989-09-12 1994-05-26 Pall Corporation Processing blood
US5133878A (en) * 1989-11-17 1992-07-28 Pall Corporation Polymeric microfiber filter medium
US5266219A (en) * 1989-12-28 1993-11-30 Pall Corporation Device and method for separating plasma from blood
US5302299A (en) * 1990-05-24 1994-04-12 Pall Corporation Biological semi-fluid processing assembly
US5863436A (en) * 1990-05-24 1999-01-26 Pall Corporation Venting system
US6086770A (en) * 1990-05-24 2000-07-11 Pall Corporation Venting system
US5151192A (en) * 1990-07-13 1992-09-29 Pall Corporation Method for removing heparin from blood or plasma
US5744047A (en) * 1990-07-27 1998-04-28 Pall Corporation Leucocyte depleting filter device and method of use
US5258127A (en) * 1990-07-27 1993-11-02 Pall Corporation Leucocyte depleting filter device and method of use
US5362406A (en) * 1990-07-27 1994-11-08 Pall Corporation Leucocyte depleting filter device and method of use
US5298165A (en) * 1990-09-25 1994-03-29 Asahi Medical Co., Ltd. Method for removing leukocytes and a filter system for removing the same
US5498336A (en) * 1991-02-22 1996-03-12 Terumo Kabushiki Kaisha Leukocyte-removing filter and leukocyte-removing apparatus furnished therewith
US5190657A (en) * 1991-07-22 1993-03-02 Lydall, Inc. Blood filter and method of filtration
WO1993001880A1 (en) * 1991-07-22 1993-02-04 Lydall, Inc. Blood filter and method of filtration
US5478470A (en) * 1991-08-22 1995-12-26 Asahi Medical Co., Ltd. Filter material for selectively removing leukocytes
US5665233A (en) * 1991-08-22 1997-09-09 Asahi Medical Co., Ltd. Filter apparatus for selectively removing leukocytes
US5443743A (en) * 1991-09-11 1995-08-22 Pall Corporation Gas plasma treated porous medium and method of separation using same
EP0570569B1 (en) * 1991-12-04 1998-02-25 Hospal Industrie A support material and biocompatible anion exchange materials
US5648070A (en) * 1991-12-04 1997-07-15 Cobe Laboratories, Inc. Biocompatible anion exchange materials
US5407581A (en) * 1992-03-17 1995-04-18 Asahi Medical Co., Ltd. Filter medium having a limited surface negative charge for treating a blood material
US5543062A (en) * 1992-10-07 1996-08-06 Asahi Medical Co., Ltd. Leukocyte-removing filter device and system and method of using thereof
US5707526A (en) * 1993-02-09 1998-01-13 Menachem Kraus Leukocyte removal method using a nitrocellulose membrane filter unit
US5820755A (en) * 1993-02-09 1998-10-13 Travenol Laboratories (Israel) Ltd. Leukocyte filter unit
US5476587A (en) * 1993-06-27 1995-12-19 Terumo Kabushiki Kaisha Leukocyte-separating filter and leukocytes remover
WO1995003113A1 (en) * 1993-07-26 1995-02-02 Pall Corporation Cardioplegia filter
DE4495438T1 (en) * 1993-07-26 1996-08-22 Pall Corp Cardioplegia filters
GB2294210A (en) * 1993-07-26 1996-04-24 Pall Corp Cardioplegia filter
GB2294210B (en) * 1993-07-26 1997-11-12 Pall Corp Cardioplegia filter
US5540841A (en) * 1993-07-26 1996-07-30 Pall Corporation Cardioplegia filter and method for processing cardioplegia fluid
US5772880A (en) * 1993-09-14 1998-06-30 Baxter International, Inc. Container with a tangential port
US5591337A (en) * 1993-09-14 1997-01-07 Baxter International Inc. Apparatus for filtering leukocytes from blood cells
US5817237A (en) * 1994-01-10 1998-10-06 Hemasure, Inc. Process for simultaneously removing leukocytes and methylene blue from plasma
US5639376A (en) * 1994-01-10 1997-06-17 Hemasure, Inc. Process for simultaneously removing leukocytes and methylene blue from plasma
US5935436A (en) * 1994-01-10 1999-08-10 Hemasure Inc. Device for simultaneously removing leukocytes and methylene blue from plasma
US6159375A (en) * 1994-01-10 2000-12-12 Hemasure, Inc. Method for removing leukocytes and methylene blue from plasma
US5902490A (en) * 1994-03-10 1999-05-11 Hemasure, Inc. Filtration method and device useable for removal of leukocytes and other blood components
US6015500A (en) * 1994-03-10 2000-01-18 Hemasure Inc. Filtration device useable for removal of leukocytes and other blood components
US5472605A (en) * 1994-03-10 1995-12-05 Hemasure, Inc. Filtration device useable for removal of leukocytes and other blood components
US6251292B1 (en) 1994-03-10 2001-06-26 Hemasure, Inc. Method of preventing air from becoming entrapped within a filtration device
US5586997A (en) * 1994-07-28 1996-12-24 Pall Corporation Bag filter
US6074869A (en) * 1994-07-28 2000-06-13 Pall Corporation Fibrous web for processing a fluid
US5582907A (en) * 1994-07-28 1996-12-10 Pall Corporation Melt-blown fibrous web
US6632191B1 (en) * 1994-10-13 2003-10-14 Haemonetics Corporation System and method for separating blood components
US5795483A (en) * 1994-10-17 1998-08-18 Baxter International Inc. Method of separating leukocytes from blood cells using a leukodepletion filter
US7422606B2 (en) 1994-10-17 2008-09-09 Edwards Lifesciences Corporation Medical devices and products having coatings applied thereto
US6306454B1 (en) 1994-10-17 2001-10-23 Baxter International Inc. Method for producing improved medical devices and devices so produced
US6045701A (en) * 1994-10-17 2000-04-04 Baxter International Inc. Method of filtering a fluid suspension with a membrane having a particular coating
US6746482B2 (en) 1994-10-17 2004-06-08 Baxter International Inc. Method for producing medical devices and devices so produced
US6648922B2 (en) 1994-10-17 2003-11-18 Baxter International Inc. Method for producing improved medical devices and devices so produced
US5972217A (en) * 1994-10-17 1999-10-26 Baxter International Inc. Blood cell separation devices having a membrane with particular coating
US20040068225A1 (en) * 1994-10-17 2004-04-08 Ung-Chhun Neng S. Method for producing improved medical devices and devices so produced
US5647985A (en) * 1994-10-17 1997-07-15 Baxter International Inc. Whole blood leukodepletion and platelet filter
US5728306A (en) * 1994-12-23 1998-03-17 Baxter International Inc. Leukodepletion filter and method for filtering leukocytes from freshly drawn blood
US5695653A (en) * 1994-12-23 1997-12-09 Pall Corporation Device and method for separating components from a biological fluid
US5885457A (en) * 1994-12-23 1999-03-23 Baxter International Inc. Filtration media for filtering leukocytes from freshly drawn blood
US5630946A (en) * 1995-02-15 1997-05-20 Pall Corporation Method for processing a biological fluid including leukocyte removal in an extracorporeal circuit
US5783094A (en) * 1995-04-13 1998-07-21 Teva Medical Ltd. Whole blood and platelet leukocyte filtration method
US5906570A (en) * 1995-04-18 1999-05-25 Cobe Laboratories, Inc. Particle filter apparatus
US6022306A (en) * 1995-04-18 2000-02-08 Cobe Laboratories, Inc. Method and apparatus for collecting hyperconcentrated platelets
US6053856A (en) * 1995-04-18 2000-04-25 Cobe Laboratories Tubing set apparatus and method for separation of fluid components
US6071422A (en) * 1995-04-18 2000-06-06 Cobe Laboratories, Inc. Particle separation method and apparatus
US5951877A (en) * 1995-04-18 1999-09-14 Cobe Laboratories, Inc. Particle filter method
US5939319A (en) * 1995-04-18 1999-08-17 Cobe Laboratories, Inc. Particle separation method and apparatus
US5722926A (en) * 1995-04-18 1998-03-03 Cobe Laboratories, Inc. Method for separating particles
US5674173A (en) * 1995-04-18 1997-10-07 Cobe Laboratories, Inc. Apparatus for separating particles
US5913768A (en) * 1995-04-18 1999-06-22 Cobe Laboratories, Inc. Particle filter apparatus
WO1996040400A1 (en) 1995-06-07 1996-12-19 Baxter International Inc. Blood processing systems which monitor citrate return
WO1996040405A1 (en) 1995-06-07 1996-12-19 Baxter International Inc. System for deriving collected blood storage parameters
US6048464A (en) * 1995-12-26 2000-04-11 Asahi Medical Co., Ltd. Filter medium for leukocyte removal, method of making, and method of using thereof
US20090014395A1 (en) * 1996-02-23 2009-01-15 Bischof Daniel F Systems and Methods for On Line Finishing of Cellular Blood Products Like Platelets Harvested for Therapeutic Purposes
US6010633A (en) * 1997-03-06 2000-01-04 Hemasure Inc. Method of preventing air from becoming entrapped within a filtration device
AU726974B2 (en) * 1997-08-28 2000-11-30 Asahi Kasei Medical Co., Ltd. Leucocyte-removing filter medium
US6051146A (en) * 1998-01-20 2000-04-18 Cobe Laboratories, Inc. Methods for separation of particles
US6274041B1 (en) 1998-12-18 2001-08-14 Kimberly-Clark Worldwide, Inc. Integrated filter combining physical adsorption and electrokinetic adsorption
US6673447B2 (en) 1998-12-18 2004-01-06 Kimberly-Clark Worldwide, Inc. Cationically charged coating on hydrophobic polymer fibers with poly (vinyl alcohol) assist
US6537614B1 (en) 1998-12-18 2003-03-25 Kimberly-Clark Worldwide, Inc. Cationically charged coating on hydrophobic polymer fibers with poly (vinyl alcohol) assist
EP1018346A3 (en) * 1999-01-07 2002-11-20 Terumo Kabushiki Kaisha Leucocyte filter and method for manufacturing same
EP1018346A2 (en) * 1999-01-07 2000-07-12 Terumo Kabushiki Kaisha Leucocyte filter and method for manufacturing same
US6280622B1 (en) 1999-02-22 2001-08-28 Gambro, Inc. System for using ligands in particle separation
US6153113A (en) * 1999-02-22 2000-11-28 Cobe Laboratories, Inc. Method for using ligands in particle separation
US6337026B1 (en) 1999-03-08 2002-01-08 Whatman Hemasure, Inc. Leukocyte reduction filtration media
WO2000053287A1 (en) * 1999-03-11 2000-09-14 Whatman, Inc. Leukocyte filter assembly, media, and method
US6334842B1 (en) 1999-03-16 2002-01-01 Gambro, Inc. Centrifugal separation apparatus and method for separating fluid components
US6514189B1 (en) 1999-03-16 2003-02-04 Gambro, Inc. Centrifugal separation method for separating fluid components
US7029430B2 (en) 1999-03-16 2006-04-18 Gambro, Inc. Centrifugal separation apparatus and method for separating fluid components
US7549956B2 (en) 1999-03-16 2009-06-23 Caridianbct, Inc. Centrifugal separation apparatus and method for separating fluid components
US7651474B2 (en) 1999-10-01 2010-01-26 Caridianbct, Inc. Method and apparatus for leukoreduction of red blood cells
US6977044B1 (en) 1999-11-01 2005-12-20 Asahi Medical Co., Ltd. Filter for selectively removing leukocytes
US6645388B2 (en) 1999-12-22 2003-11-11 Kimberly-Clark Corporation Leukocyte depletion filter media, filter produced therefrom, method of making same and method of using same
US6354986B1 (en) 2000-02-16 2002-03-12 Gambro, Inc. Reverse-flow chamber purging during centrifugal separation
US20050148748A1 (en) * 2000-05-17 2005-07-07 Terumo Kabushiki Kaisha Copolymers and blood filter using the same
US20020000403A1 (en) * 2000-05-17 2002-01-03 Masaru Tanaka Copolymers and blood filter using the same
US8524090B2 (en) * 2000-07-10 2013-09-03 Asahi Kasei Medical Co., Ltd. Blood processing filter
US20100051533A1 (en) * 2000-07-10 2010-03-04 Asahi Medical Co., Ltd Blood processing filter
US6590054B2 (en) 2000-09-29 2003-07-08 Terumo Kabushiki Kaisha Antithrombotic surface treating agent and medical apparatus
EP1192959A2 (en) * 2000-09-29 2002-04-03 Terumo Kabushiki Kaisha Antithrombotic surface treating agent and medical apparatus
EP1192959A3 (en) * 2000-09-29 2002-04-10 Terumo Kabushiki Kaisha Antithrombotic surface treating agent and medical apparatus
US20040104165A1 (en) * 2001-01-29 2004-06-03 Teruhiko Oishi Filter for processing blood and process for producing the same
US7156240B2 (en) * 2001-01-29 2007-01-02 Asahi Kasei Medical Co., Ltd. Filter for processing blood and process for producing the same
WO2002060557A1 (en) * 2001-01-29 2002-08-08 Asahi Medical Co., Ltd. Filter for processing blood and process for producing the same
US20050121386A1 (en) * 2001-03-12 2005-06-09 Yukihiro Yamada Filter for selectively eliminating leukocytes
US7721898B2 (en) * 2001-07-31 2010-05-25 Asahi Kasei Medical Co., Ltd. Coating material for leukocyte removal filter and the filter
US20040253204A1 (en) * 2001-07-31 2004-12-16 Yasuhiko Yagi Polymer for coating leukocyte removal filter material and the filter material
US20050014127A1 (en) * 2001-10-16 2005-01-20 Hirokazu Onodera Method for selectively removing virus and leukocytes eliminating material and eliminating apparatus
US7820371B2 (en) 2001-10-16 2010-10-26 Asahi Kasei Kuraray Medical Co., Ltd. Method for removing viruses and leukocytes from blood using a surface comprising hydroxyl and polyethylene glycol groups
US20070248942A1 (en) * 2001-10-16 2007-10-25 Asahi Medical Co., Ltd. Method for selectively removing virus and leukocytes, removing material and removing apparatus
EP1452193A1 (en) * 2001-12-03 2004-09-01 ASAHI MEDICAL Co., Ltd. Filter for selectively eliminating leukocytes
US7410066B2 (en) * 2001-12-03 2008-08-12 Ashai Kasei Medical Co., Ltd Filter for selectively eliminating leukocytes
EP1452193A4 (en) * 2001-12-03 2008-06-18 Asahi Kasei Kuraray Medical Co Filter for selectively eliminating leukocytes
US7264608B2 (en) 2001-12-05 2007-09-04 Fenwal, Inc. Manual processing systems and methods for providing blood components conditioned for pathogen inactivation
US20080050275A1 (en) * 2001-12-05 2008-02-28 Bischof Daniel F Manual processing systems and methods for providing blood components conditioned for pathogen inactivation
US20030104349A1 (en) * 2001-12-05 2003-06-05 Baxter International Inc. Manual processing systems and methods for providing blood components conditioned for pathogen inactivation
US7789847B2 (en) 2001-12-10 2010-09-07 Caridianbct, Inc. Methods and apparatus for leukoreduction of red blood cells
US20070282242A1 (en) * 2001-12-10 2007-12-06 Gambro Bct, Inc. Methods and Apparatus for Leukoreduction of Red Blood Cells
US20060184086A1 (en) * 2001-12-10 2006-08-17 Gambro, Inc Methods and Apparatus For Leukoreduction of Red Blood Cells
US7052606B2 (en) 2001-12-10 2006-05-30 Gambro, Inc. Methods and apparatus for leukoreduction of red blood cells
US7682329B2 (en) 2001-12-10 2010-03-23 Caridianbct, Inc. Methods and apparatus for leukoreduction of red blood cells
US20030106861A1 (en) * 2001-12-10 2003-06-12 Gibbs Bruce M. Methods and apparatus for leukoreduction of red blood cells
US20030173274A1 (en) * 2002-02-01 2003-09-18 Frank Corbin Blood component separation device, system, and method including filtration
US20030189003A1 (en) * 2002-04-08 2003-10-09 Menahem Kraus Leukocyte filter construction
US6767466B2 (en) * 2002-04-08 2004-07-27 Teva Medical Ltd. Leukocyte filter construction
US20090127206A1 (en) * 2002-04-16 2009-05-21 Caridianbct, Inc. Blood Component Processing System Method
US7708889B2 (en) 2002-04-16 2010-05-04 Caridianbct, Inc. Blood component processing system method
US7279107B2 (en) 2002-04-16 2007-10-09 Gambro, Inc. Blood component processing system, apparatus, and method
US7497944B2 (en) 2002-04-16 2009-03-03 Caridianbct, Inc. Blood component processing system, apparatus, and method
US20060088941A1 (en) * 2002-05-20 2006-04-27 Portascience Inc Method and apparatus for measuring white blood cell count
US6709868B2 (en) 2002-05-20 2004-03-23 Portascience Inc. Method and apparatus for measuring white blood cell count
US20070029256A1 (en) * 2003-08-07 2007-02-08 Yasuhiro Nakano Composite porous membrane and process for producing the same
US8999167B2 (en) 2003-08-07 2015-04-07 Asahi Kasei Medical Co., Ltd. Composite porous membrane and process for producing the same
US20050137517A1 (en) * 2003-12-19 2005-06-23 Baxter International Inc. Processing systems and methods for providing leukocyte-reduced blood components conditioned for pathogen inactivation
US8101431B2 (en) 2004-02-27 2012-01-24 Board Of Regents, The University Of Texas System Integration of fluids and reagents into self-contained cartridges containing sensor elements and reagent delivery systems
US20080190843A1 (en) * 2004-08-13 2008-08-14 Hitoshi Mizomoto Polymers Useful as Medical Materials
US20080190842A1 (en) * 2004-08-13 2008-08-14 Hitoshi Mizomoto Polymers Useful as Medical Materials
WO2006016166A1 (en) * 2004-08-13 2006-02-16 Asahi Kasei Kabushiki Kaisha Polymers useful as medical materials
US7793787B2 (en) 2004-08-13 2010-09-14 University Of Southampton Polymers useful as medical materials
WO2006016163A1 (en) * 2004-08-13 2006-02-16 Asahi Kasei Kabushiki Kaisha Polymers useful as medical materials
US8136676B2 (en) 2004-08-13 2012-03-20 University Of Southampton Polymers useful as medical materials
US20160106779A1 (en) * 2004-08-20 2016-04-21 Allan Mishra Neutrophil-depleted whole blood and platelet rich plasma compositions
US8377398B2 (en) 2005-05-31 2013-02-19 The Board Of Regents Of The University Of Texas System Methods and compositions related to determination and use of white blood cell counts
US20100291588A1 (en) * 2005-06-24 2010-11-18 The Board Of Regents Of The University Of Texas System Systems and methods including self-contained cartridges with detection systems and fluid delivery systems
US20070118063A1 (en) * 2005-10-05 2007-05-24 Gambro, Inc Method and Apparatus for Leukoreduction of Red Blood Cells
CN101053683B (en) 2006-02-20 2010-12-15 旭化成医疗株式会社 Method for filtering blood or blood components and filter device
WO2007134191A1 (en) * 2006-05-10 2007-11-22 Board Of Regents, The University Of Texas System Detecting multiple types of leukocytes
US20080038738A1 (en) * 2006-05-10 2008-02-14 The Board Of Regents Of The University Of Texas System Detecting tumor biomarker in oral cancer
US20100270232A1 (en) * 2007-12-27 2010-10-28 Toray Industries, Inc. Fiber construct for treating biological components
US9457134B2 (en) 2009-03-30 2016-10-04 Terumo Kabushiki Kaisha Surface treating agent, filtering material for filter, and blood treatment filter
WO2010113632A1 (en) 2009-03-30 2010-10-07 テルモ株式会社 Surface-treating agent, filtering material for filter, and blood treatment filter
US9186441B2 (en) 2009-03-30 2015-11-17 Terumo Kabushiki Kaisha Surface treating agent, filtering material for filter, and blood treatment filter
CN102397724A (en) * 2010-09-16 2012-04-04 私立中原大学 Filter medium for leukocyte removal and filter method
US9248446B2 (en) 2013-02-18 2016-02-02 Terumo Bct, Inc. System for blood separation with a separation chamber having an internal gravity valve
US10238786B2 (en) 2013-03-27 2019-03-26 Macopharma, S.A.S. Leukocyte filtration unit with reduced platelet adhesion
EP2783717A1 (en) 2013-03-27 2014-10-01 Maco Pharma Leucocyte filtration unit with reduced platelets adherence
CN104117230B (en) * 2013-04-24 2017-05-17 富士胶片株式会社 Filter, filtering method, acylate cellulose film and making method thereof
CN104117230A (en) * 2013-04-24 2014-10-29 富士胶片株式会社 Filter, filtering method, acylate cellulose film and making method thereof
US10214727B2 (en) 2013-06-04 2019-02-26 Allan Mishra Platelet-rich plasma compositions and methods of preparation
US9782707B2 (en) 2014-03-24 2017-10-10 Fenwal, Inc. Biological fluid filters having flexible walls and methods for making such filters
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US9968738B2 (en) 2014-03-24 2018-05-15 Fenwal, Inc. Biological fluid filters with molded frame and methods for making such filters
US10159778B2 (en) 2014-03-24 2018-12-25 Fenwal, Inc. Biological fluid filters having flexible walls and methods for making such filters
US10183475B2 (en) 2014-03-24 2019-01-22 Fenwal, Inc. Flexible biological fluid filters
US9796166B2 (en) 2014-03-24 2017-10-24 Fenwal, Inc. Flexible biological fluid filters
US10376627B2 (en) 2014-03-24 2019-08-13 Fenwal, Inc. Flexible biological fluid filters
CN106457205A (en) * 2014-07-22 2017-02-22 旭化成医疗株式会社 Adsorbent for removing histone and purification device for liquid derived from living organism
CN106319966A (en) * 2016-08-18 2017-01-11 南京双威生物医学科技有限公司 Processing method of leucocyte filter membrane
CN106319966B (en) * 2016-08-18 2019-08-16 南京双威生物医学科技有限公司 A kind of processing method of leukocyte filter membranes

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EP0267286A1 (en) 1988-05-18
JPH0651060B1 (en) 1994-07-06
DE3785993D1 (en) 1993-07-01
EP0267286A4 (en) 1989-12-04
DE3785993T2 (en) 1994-02-10
WO1987005812A1 (en) 1987-10-08
EP0267286B1 (en) 1993-05-26

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